Presentation Information
[PCP2-05]Numerical Simulation of Effect of Current Injection on Vortex Penetration/expulsion Fields in Mesoscopic Superconductors
Ayumu Takahashi1, Shota Oshiro1, Takumi Mataba1, Masahiko Hayashi2, *Akinobu Kanda1 (1. Univ. Tsukuba (Japan), 2. Akita Univ. (Japan))
Keywords:
Mesoscopic superconductors,Vortex,Current Injection
[Purpose] In mesoscopic type-II superconductors, where the size is several times the coherence length, a small number of vortices can exist in a magnetic field and characteristic vortex states such as giant vortex states and multivortex states appear. In such few-vortex systems, it was pointed out that the number and configuration of vortices can be controlled by external parameters such as external magnetic fields and injected currents.1) In an experiment where a constant current was applied between the centers of two adjacent sides of a mesoscopic square superconductor, while sweeping the magnetic field, it was demonstrated that the vortex penetration/expulsion field exhibits complex dependence on the magnitude and direction of the injected current.2) The origin of the effect should be related to the Lorentz force exerted on the vortices. However, the details remain unclear. This study aims to explain the results of this early experiment through numerical calculations.
[Method] We used a program, pyTDGL,3) which solves the TDGL equation for two-dimensional superconductors, and investigated the effect of current injection on the vortex penetration/expulsion fields. The sample is a square superconductor with a side length of 1.1 μm and a thickness of 40 nm with superconducting leads 0.3 μm wide attached to the centers of two adjacent sides. We assumed an aluminum film.
[Results] From the time-evolution of the amplitude of the superconducting order parameter under current injection, it is shown that the position of the vortex penetration/expulsion strongly depends on the injected current. This effect qualitatively explains the complicated behavior observed in Ref. 2).
References
1) M.V. Milosevic, A. Kanda, S. Hatsumi, F.M. Peeters, Y. Ootuka, Phys. Rev. Lett. 103, 217003 (2009).
2) S. Hatsumi, Y. Ootuka, A. Kanda, Physica C 469, 1080 (2009).
3) L. Bishop-Van Horn, Comput. Phys. Commun. 291, 108799 (2023).
[Method] We used a program, pyTDGL,3) which solves the TDGL equation for two-dimensional superconductors, and investigated the effect of current injection on the vortex penetration/expulsion fields. The sample is a square superconductor with a side length of 1.1 μm and a thickness of 40 nm with superconducting leads 0.3 μm wide attached to the centers of two adjacent sides. We assumed an aluminum film.
[Results] From the time-evolution of the amplitude of the superconducting order parameter under current injection, it is shown that the position of the vortex penetration/expulsion strongly depends on the injected current. This effect qualitatively explains the complicated behavior observed in Ref. 2).
References
1) M.V. Milosevic, A. Kanda, S. Hatsumi, F.M. Peeters, Y. Ootuka, Phys. Rev. Lett. 103, 217003 (2009).
2) S. Hatsumi, Y. Ootuka, A. Kanda, Physica C 469, 1080 (2009).
3) L. Bishop-Van Horn, Comput. Phys. Commun. 291, 108799 (2023).